Chandrapala Weerasuriya can’t remember when he last took his medication. The 67-year-old retired businessman, living in Sri Lanka’s Gampaha district, has always relied on a drug to keep at bay his hereditary nervous condition, which makes him dizzy and unable to walk.

But since his prescription recently ran out, he cannot get another supply. The drug is simply not available in Sri Lanka any more.

“I am afraid that I might become paralysed because there is no one to care for us,” he said fretfully. “My wife and I do everything alone. We split the household chores and manage it between ourselves. My wife has a knee problem and she can barely walk.”

Sri Lanka’s financial crisis, its worst since independence, is swiftly becoming an alarming health crisis. The government’s coffers have fallen to their lowest levels on record and last week the country was forced to default on its international loans for the first time in its history. Without crucial foreign currency, Sri Lanka has been unable to import the essentials: food, fuel – and medicine.

Sri Lanka imports more than 80% of its medical supplies. Now almost 200 medical items are in shortage, including 76 essential, life-saving drugs, from blood-thinners for heart attack and stroke patients to antibiotics, rabies vaccines and cancer chemotherapy drugs. Essential surgical equipment and anaesthesia is running out so fast that the decision was made this week for only emergency surgeries, mostly heart and cancer patients, to go ahead. All routine surgeries – anything from hernias to swollen appendixes – have been put on hold. Some government hospitals have been instructed to only admit emergency patients.

“Ultimately, people are definitely going to die,” said a doctor in Colombo who had been told not to speak to the media.

She described how the hospital was so low on certain drugs they had to instruct families of patients to go out to pharmacies and try to buy it themselves. “There have been incidents where the family members have gone around looking for drugs and by the time they’ve come back with the drug, it’s been too late and the patient has died,” she said.

The doctor said the shortages were getting worse. “I’m worried about pregnant mothers because soon I don’t know whether we will have enough drugs to perform cesarian sections,” she said.

Cancer drugs, which are notoriously expensive to import, have been particularly badly hit by shortages in recent weeks, and the responsibility to source them has fallen on the heads of oncologists themselves. They have been putting out global appeals for donations, and writing letters to private supporters, organisations and governments, to ensure cancer treatments are not delayed.

Dr Buddhika Somawardana, an oncologist at Colombo’s largest cancer hospital, described the “great stress” he and other doctors were under as essential cancer drugs began to run out over a month ago or stopped being available at all.

“One of the drugs we give patients undergoing chemotherapy, which boosts their blood count so they aren’t liable to serious infections, is not available any more,” he said. “So far, we managed to get donation of 80,000 vials. But that will not last very long.”

He added: “Somehow, thanks to donations, we have mostly been managing without any huge issues. But we had to postpone some chemotherapy, which may have detrimental effects on the cancer outcome.”

Somawardana said the crisis was placing a huge “financial and psychological burden” on cancer patients, who were having to source and pay vast sums for their own medicines to continue their treatment, previously free and easily accessibly in hospitals under Sri Lanka’s lauded universal healthcare system.

Cancer doctors too were feeling the pressure of having to be the ones both to appeal for global drug donations, as well as treat their patients. “I didn’t know how long we will be able to go on like this,” he said.

Ruvaiz Haniffa, a doctor in Colombo, expressed his frustration that doctors had “seen this coming as early as January” but little had been done by authorities to set up backup plans to ensure no medicines ran short, even as the country’s foreign reserves began to deplete to worryingly low levels.